Fix type in download_vctk.sh (#1739)

typo in comment

recipes/vctk/download_vctk.sh

@@ -2,7 +2,7 @@
 # take the scripts's parent's directory to prefix all the output paths.
 RUN_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )"
 echo $RUN_DIR
-# download LJSpeech dataset
+# download VCTK dataset
 wget https://datashare.ed.ac.uk/bitstream/handle/10283/3443/VCTK-Corpus-0.92.zip -O VCTK-Corpus-0.92.zip
 # extract
 mkdir VCTK